ACR LGT OVER ROTATED ON TKOF; STRUCK AND DAMAGED TAIL SKID.

Narrative

F/A RPTED 3 DISTINCT TAILSKID STRIKES IN RAPID SUCCESSION DURING ROTATION ON TKOF. TAILSKID WARNING LIGHT ON WITH LEFT GEAR UP. RECYCLED LEFT GEAR. NORMAL INDICATIONS GEAR DOWN. TAILSKID CAUTION LIGHT ON WITH GEAR UP. PROCEEDED TO MSP EMPLOYING PRECAUTIONS PRESCRIBED BY ACFT MANUAL. CLB AND CRS PERFORMANCE WERE NORMAL SUGGESTING TAILSKID WAS RETRACTED. NORMAL LNDG AT MSP. MAINT INSPECTION REVEALED THAT TAILSKID HAD SEPARATED FROM SHOCK ABSORBENT CYLINDER. IT WAS DANGLING STRAIGHT DOWN AND WAS NOT FUNCTIONAL. EVIDENCE OF HAVING BEEN STRUCK FROM BEHIND--POSSIBLY BY A RAMP VEH. TAILSKID WAS OK AT TIME OF PREFLT INSPECTION AT BOS (20 MIN PRIOR TO DEP). CREW HAD NO WAY OF KNOWING TAILSKID WAS NOT FUNCTIONAL BASED ON COCKPIT INDICATIONS. SUPPLEMENTAL INFORMATION FROM ACN 81110: UPON LNDG WE DISCOVERED THE BOTTOM OF THE SKID TO BE COMPLETELY SHEARED AWAY FROM THE MAIN CYLINDER; HANGING ON ONLY BY A CONNECTING CHAIN. A F/A HAD NOTED THAT SHE AND SEVERAL OTHER PAX HAD HEARD AN AUDIBLE 'TIC-TIC-TIC' RIGHT AROUND LIFT-OFF; AS IF SOMETHING HAD BEEN DRAGGING ON THE RWY. IN EXAMINING THE SKID THE CAPT BROUGHT UP SEVERAL POSSIBLE EXPLANATIONS. THE ONE HE CONSIDERED MOST PLAUSIBLE WAS THAT SOMEONE OR SOMETHING HAD HIT THE SKID WITH A SIDEWAYS MOTION (CONJECTING ON POSSIBLY THE BAGGAGE TRUCK; GALLEY TRUCK; ETC); SINCE IN HIS ESTIMATION; TAKING OFF AND SUBSEQUENTLY STRIKING THE SKID WOULD NOT HAVE CAUSED THE RIVETS HOLDING THE BOTTOM OF THE SKID TO THE REST OF THE CYLINDER TO SHEAR AWAY. THEN HE QUESTIONED MY PREFLT--HAD I NOTICED ANYTHING UNUSUAL ABOUT THE SKID? DID IT APPEAR TO HAVE BEEN DAMAGED PREVIOUSLY? ANSWERING IN THE NEGATIVE; I INFORMED HIM THAT I DID NOT APPRECIATE THE VOTE OF CONFIDENCE; AND WONDERED QUIETLY IF HE WAS NOT TRYING TO REFLECT RESPONSIBILITY FROM HIMSELF (IT WAS HIS TKOF). I HAD TOLD HIM THAT I HAD HEARD A NOISE JUST AT LIFT-OFF; BUT THOUGHT IT HAD COME FROM THE GALLEY DIRECTLY BEHIND ME.